Managing nitrogen to restore water quality in China

Quantifying a nitrogen ‘boundary’ in complex environments is crucial for managing local water quality. This study combines water quality observations and simulated nitrogen discharge from agricultural and other sources to estimate nitrogen discharge into waters across China.

In this article in Nature, Dag Hessen and colleagues combine a vast observational dataset on the concentrations of total nitrogen in water bodies and used nitrogen balance models to estimate local nitrogen discharge into the inland aquatic environment for the years 1955–2014. They then empirically identified the critical nitrogen-discharge threshold for each province as the total anthropogenic nitrogen discharge during the year in which pollution levels first breached the water-quality standard. Overall anthropogenic nitrogen is entering freshwaters in China at a rate nearly three times higher than the estimated ‘safe’ level. The article also discusses potential remedies and evaluates the costs of such strategies.

Published Mar. 29, 2019 10:14 AM - Last modified Mar. 29, 2019 10:14 AM